Background of Fillers
‘Fillers’ are one of the most widely performed in cosmetic medical procedures all over the world. Recently, on the YouTube, various opinions about the controversy over the side effects of HA fillers have become a hot topic. How much do we know about fillers? Let’s look at the hyaluronic acid fillers, which are the most used among dermal fillers of various ingredients.
The development of supplementary ingredients that can replace the ingredients of human tissue that decrease with aging has been in progress for a long time. At first, ingredients that do not exist in the human body, such as silicone or PMMA, were used, which had the advantage of long lasting, but had the disadvantage that it could cause an excessive immune response since it is an external material. In addition, when unwanted results such as side effects appeared, there was no way to remove them other than surgery.
Why Hyaluronic acid (HA) is popular
That is the reason why doctors use Hyaluronic acid (HA) now. Hyaluronic acid (HA) is a ingredient that is basically present in various human tissues, such as the skin, joints, and eye mucosa, and is repeatedly decomposed and regenerated every day. There is an enzyme hyaluronidase that breaks down hyaluronic acid in our body, so even if you make a filler with hyaluronic acid and inject it, the hyaluronic acid is naturally decomposed and disappears. Even if the injected filler becomes a problem, hyaluronidase can be injected externally to dissolve it, so hyaluronic acid has become widely used as a filler ingredient.
Hyaluronic acid in its natural state is easily decomposed and disappears within a few days. Therefore, hyaluronic acid fillers are made by adding a crosslinking agent to hyaluronic acid to prolong the maintenance period. A crosslinking agent is a substance that bridges and connects molecules between molecules. By binding the crosslinking agent to hyaluronic acid, that is, it makes the hyaluronic acid agglomerate, so it is less attacked by enzymes and can last longer. The process of making hyaluronic acid into a gel form through this cross-linking is ‘cross linking’, and various filler products are created through unique cross-linking technology for each filler manufacturer.
What is the difference between Monophasic and Biphasic
The viscosity and elasticity of hyaluronic acid fillers vary depending on the number of cross-linking, and they are largely divided into two types: Monophasic and Biphasic. If the hyaluronic acid is more densely combined through multiple cross-linking, the filler is hard and well aggregated. Monophasic is a filler in the form of a single gel, and biphasic is a filler in the form of particles contained in a gel. As for the products distributed in the market, representative monophasic fillers include Juvéderm, Elravie, E.p.t.q., etc., and biphasic fillers include Restylane, Yvoire, and Perfectha.
Monophasic and biphasic, both have their own pros and cons.
Dr. Jae Yoon Jung, owner and president of Oaro dermatologic clinic, said, “The monophasic filler has very small particles, so even if it is injected, it cannot increase the volume much, but it does not flow well and stays in the area well. It has advantage for looking naturally and is mainly used for areas such as under the eyes. The biphasic filler has strong elasticity that allows it to return even if it is subjected to an external shock, so it is good to give volume and maintain its shape well. I prefer biphasic fillers for areas that require a lot of volume, such as the nose, front cheekbones, and nasolabial folds.”
These days, many filler manufacturers combine the advantages and disadvantages of monophasic and biphasic and are releasing intermediate fillers that are neither too thin nor too hard and they have several product lines according to their viscosity.
Crosslinking agent control for safety
- Crosslinking agent control
Biphasic fillers contain a lot of crosslinking agents as they undergo crosslinking several times. Since crosslinking agents are chemical ingredients, the more they contain, the more side effects such as swelling, inflammation, allergic reactions, and delayed immune reactions can occur. This means that during manufacturing 'how well the crosslinking agent is washed off' after crosslinking is the key to safety. - Type of crosslinking agent
Crosslinking agents currently used in the crosslinking process include 'BDDE (ButaneDiol Diglycidyl Ether)', 'PEG (Polyethylene Glycol)', and 'DVS (DiVinyl Sulfone)'. I used to use DVS a lot in the past, but as a lot of side effects appeared, the usage rate dropped, and now I mainly use BDDE. It is no exaggeration to say that most hyaluronic acid fillers use BDDE. Recently, a filler using PEG, which is known to have less toxins than BDDE, has been released. - MoD (The degree of modification)
In determining the safety of the filler, the ‘MoD (The degree of modification)’ value, which shows how much natural hyaluronic acid has been deformed until it is made into a final product, is also important. MoD is measured according to the total amount of fully crosslinked BDDE and under pendant BDDE. A lower MoD value means less BDDE and less modification.
Advise before you get filler treatment
As the usage of fillers increases, manufacturing technology develops, and fillers with good performance and safety are being made. It is important to choose a good filler, but more importantly, how to safely get the treatment.
Dr. Jae Yoon Jung said, “The filler itself is important, but it is also important to have a doctor who knows the anatomy well and has a lot of experience in filler treatment, as there are cases where it irritates blood vessels or nerves during the injection. If properly made fillers are injected in the right way, fillers can be of great help.”
